I was duty helmsman on a cutter in complete zero visibility fog. Radar displayed a "large object" and our new ensign determined it was a charted small island. We made a course correction and proceeded ahead slow. Radar announced "the island" was moving on intercept.The ensign replied to maintain our heading. Within seconds I could feel a "bite" in the swells and made a light adjustment to the wheel. A few seconds later I was furiously yanking with all my strength to port as a monster supertanker passed within several meters. The ensign lost all decorum and was yelling " hang a left, for God's sake hang a left!" I managed to reply "hanging a left aye sir ! " The chief calmly freshened our coffees and talked about floating islands in nautical folklore. The ensign became a very good officer. He learned his lesson and so did you. Being humble ( and lucky enough) to share and learn from mistakes makes us all better ;O)